There are thousands of unpublished authors out there wanting to become published ones – many of them writing with a children's readership in mind. You only have to spend a few minutes on Facebook or Twitter or browsing the various blogs and websites to see the networks and communities that have sprung up globally for such writers to support and encourage one another, sharing tips and information.

Inevitably, the self-appointed label of "unpublished author" covers the whole range of people, from those who like the idea of being an author but have never knuckled down to the actual writing part, to some very accomplished writers who just need that lucky break.

SCBWI – the Society of Children's Book Writers and Illustrators – does much to support and encourage unpublished writers. In the UK, its annual Undiscovered Voices competition culminates in the publication of an anthology of excerpts from the best of the unpublished children's fiction novels, submitted by its members. This is then sent to children's book agents and editors in the hope that these undiscovered voices will not remain undiscovered for long.

One such find was Paula Rawsthorne's The Truth About Celia Frost. Although Rawsthorne, a former teacher and social worker, is not new to published short-story writing, this is her first novel.

At first, it appears that Celia Frost – a 14-year-old red-headed schoolgirl – is suffering from haemophilia, or some such disorder, where a simple cut could cause her to bleed to death because her blood won't clot. Then there is the growing possibility that, in truth, there's nothing wrong with Celia at all: that her mother, Janice, is suffering from the likes of Munchausen by proxy, lying to Celia and feigning her illness … but the truth? The truth is far more sinister.

Despite Rawsthorne's social-work background, The Truth About Celia Frost is more of a fast-paced chase thriller than a slice of social realism. Part of its appeal is that it's straightforward and uncomplicated, and the ducking and diving is so localised. Much of the story takes place in and around a housing estate, or in a water-filled, disused quarry.

The very fact that the story remains within this microcosm, rather than breaking out into, say, an Alex Rider style adventure, or the fugitive-in-hiding feeling of Kevin Brooks's Being, is a part of what makes Celia Frost different. And, like the main protagonist in Being, the truth about Celia Frost, the character, makes her very different from the rest of us too.

Although none of the characters is multidimensional – this isn't an angst-ridden young-adult tale, but is for younger readers – Rawsthorne is adept at making the reader regularly change their attitude towards them.

In addition to Janice, who hits the bottle when things get really bad, there's Frankie, the ex-policeman turned private investigator, whose attitude to the law seems particularly pertinent in the current phone-hacking climate. Running the FBI (Frankie Byrne Investigations, a one-man outfit), he has a plethora of fake IDs, and very adaptable "morals". The real villain of the piece, though, is his client.

The Truth About Celia Frost is not without its faults, but it's fast and fun, and difficult to pigeon-hole, which is no bad thing in this age of rigid genres. What's more, I found myself caring about the central characters and – despite the relevance of blood in the story – I'm delighted to report that this book is guaranteed vampire-free.

• Philip Ardagh's omnibus edition of The Eddie Dickens Trilogy is published by Faber.